Organic materials: sources of nitrogen in the organic production of lettuce

Authors : Maja MANOJLOVIC, Ranko CABILOVSKI, Martina BAVEC

Pages : 163-172

View : 14 | Download : 7

Publication Date : 2010-04-01

Article Type : Research Paper

Abstract :This paper presents the results of 2 experiments: an incubation experiment and a subsequent field experiment. An incubation experiment was set up in order to determine the mineralization potential of different organic materials insert ignore into journalissuearticles values(OMs); insert ignore into journalissuearticles values(well-rotted farmyard manure [FTM], guano [G], soybean seed [S], and forage pea seed [P]);, the kinetics of mineral nitrogen insert ignore into journalissuearticles values(N); release, and the correlation between OM content and the quantity of mineralized N. The results of the incubation experiment were checked under field conditions in which different OMs were used as N sources for lettuce insert ignore into journalissuearticles values(Lactuca sativa L.);. The highest mineralization rate constant k insert ignore into journalissuearticles values(0.127 day-1); and net mineralization rate insert ignore into journalissuearticles values(NM); insert ignore into journalissuearticles values(76.37% of total applied N); were obtained with G, and the lowest k insert ignore into journalissuearticles values(0.098 day-1); and NM insert ignore into journalissuearticles values(30.12% of total applied N); were obtained with FYM. In the field experiment in 2007 and 2008 we applied different OM sources that contained the same amount of potentially mineralizable N insert ignore into journalissuearticles values(40 and 35 kg N ha-1, respectively);, calculated on the basis of k and NM. The use of OMs increased the concentration of mineral N in the soil and increased the yield of fresh lettuce. Nitrate content in the fresh lettuce was within acceptable limits both years insert ignore into journalissuearticles values(
Keywords : Key words Lettuce, nitrogen, organic farming, potentially mineralizable N